Albert Einstein said, "Imagination is more important than knowledge, for knowledge is limited, while imagination embraces the world."

In the world of inventing I would then interpret that quote to be, "It is far harder to create an idea that will change the world forever than it is to simply assemble that same idea."

I will give you an example. If I asked you to make me a pencil, what would you need? A cylinder of graphite and a shaft of wood to hold it in. What's more impressive and harder to do? What is more impressive and harder to do is to be that individual who over 400 years ago cried out in disdain over having their current writing utensil making a mess all over their hands and from that point forward decide that what they needed was a self-contained writing apparatus.

In the same vein, sliced bread had been around for hundreds of years before anyone thought of taking two slices and making a sandwich out of it. Now in the US alone we consume over 300 million sandwiches per day.